Most kinds of apparatus, such as e.g. a photographic camera, a processor for exposed materials, an optoelectronic scanner, a xerographic copier, or a thermal printer, are mounted within a generally rectangular housing, which may include a rectangular metal frame for supporting various parts of the apparatus.
In many of these apparatus, the metal frame is made up at least in part from panels and the mechanical geometry of the frame panels, especially the relative distance between them, is very important in order to guarantee that the apparatus be of good quality and operate reliably.
The frame of the apparatus thus has to be designed and manufactured to satisfy rather small and demanding tolerances, thereby minimising the creation of disturbing gaps or separation between panels. In addition, the frame thus formed needs a geometry which requires no adjustment after assembly and which remains stable over time.
In one prior art instance, precise positioning and fastening of two panels in an apparatus was generally accomplished in a rather complicated way, including crossbars which were either manually adjustable in length or were available in fixed high precise manufactured lengths.
In another prior art context, in order to save mounting time, screw receptacles were used as disclosed in U.S. Pat. No. 3,967,432 and in "Research Disclosure" no 34449 (Dec. 1992). However, even with these techniques, supplementary positioning means are still needed in practice for assembling the panels, with inevitable increased material costs. In addition, this second prior art teaching does not guarantee high geometrical precision in the positions of the panels in question.